A transceiver is used in communication systems for transmitting and receiving information or data. The transceiver is of generally two types namely, a full-duplex transceiver and a half-duplex transceiver. The half-duplex transceiver is used in applications that do not require simultaneous transmission and reception of data. The half-duplex transmitter includes a transmitter subsystem and a receiver subsystem operating in transmission phase and reception phase, respectively, in different time periods. For example, during the transmission phase, the transmitter subsystem is in active state and the receiver subsystem is in an inactive state, and vice-versa in the reception phase. However, during a reception phase, even though elements of the transmitter subsystem are in the inactive state, power is still being supplied by a direct current to direct current (DC-DC) converter to components, for example, a power amplifier (PA) of the transmitter subsystem of the half-duplex transceiver. Such supply of power to components of the transmitter subsystem during the reception phase results in unnecessary power consumption. Moreover, it is not feasible to switch the DC-DC converter between an ON-state and an OFF-state for every transition between the transmitter phase and the receiver phase, as a settling time of the DC-DC converter is generally higher than a turn-around time or transition time between the receiver subsystem and the transmitter subsystem. For example, a turn-around time of the receiver subsystem to the transmitter subsystem is around 4 micro seconds that is significantly smaller as compared to a settling time of the DC-DC converter, for example, 300 micro seconds.
In one technique, the DC-DC converter can be configured to toggle between a pulse width modulation (PWM) mode for the transmission phase and a pulse frequency modulation (PFM) mode for the reception phase to save the battery current. However, the switching time between the two modes (PWM and PFM) is still significantly greater than the turn-around time between the transmitter subsystem and the receiver subsystem, and accordingly, such a technique limits the speed of transition between the transmitter subsystem and the receiver subsystem and also increases the number of circuit elements for the PFM mode or to support operations of the PFM mode.